Otoscopes and otoscopy
Position of otoscope for ear exam
An ear exam can find problems in the ear canal, eardrum, and the middle ear. During an ear exam, a tool
called an otoscope is used to look at the outer ear canal and eardrum. The otoscope has a light, a
magnifying lens, and a funnel-shaped viewing piece with a narrow, pointed end called a speculum.
The doctor holds the otoscope in one hand and uses his or her free hand to pull the outer ear gently up
and back. This straightens the ear canal and helps the doctor see inside the ear. In babies younger than
12 months, the doctor will gently pull the outer ear down and back.
If you are doing a home ear exam with an otoscope, be sure to look into the otoscope before you move it
forward. Make sure you can see the path of the ear canal. You do not need to insert the viewing piece
very far into the ear. Angle the tip of the viewing piece slightly toward the person's nose to follow the
normal path of the canal. While you look through the otoscope, move it gently at different angles so that
you can see the ear canal walls and the eardrum. Stop at any sign of increased pain.
Examine the good ear first
Examine the good ear first. This has several advantages: it prevents the spread of infection into
an unaffected ear, it usually allows you to see some normal anatomy with which to compare the
other side, and also helps stop you relaxing once you have identified one abnormality, failing to
see less obvious but often more important findings - a common problem of students. With the
light source turned up full, use the otoscope as a torch to examine the pinna briefly for meatal
abnormalities and previous surgical wounds.
The commonest scars around the ear are those from postaural and endaural incisions. Eczema
around the meatus usually indicates the presence of otitis externa. With your free hand, gently
pull the pinna upwards and backwards to straighten the external ear canal. This is not usually
necessary in young children as the canal is straighter. While resting the side of your hand against
the patient's temple introduce the speculum gently into the canal. The patient may cough as the
cutaneous branch of the vagus is stimulated.
What to look for
Examine the external canal and the tympanic membrane systematically. You should learn figure
3 thoroughly because if you are not sure what you should be looking for you will undoubtedly
miss things.
Firstly, look at the external canal wall. Does the skin look normal or is it inflamed with debris in
the canal (otitis externa)? Next identify the handle of the malleus. If it is not immediately
obvious then look for its lateral process, which is rarely absent.
You should then inspect the pars tensa systematically, starting in the posterosuperior quadrant
and then moving forwards, downwards, and backwards until all 360?has been covered. Try to
identify as many structures as you can. Finally, carefully inspect the pars flaccida - this is where
abnormalities are often missed.
To make sure you do not miss anything ask yourself the following questions.
Can I clearly see all the external auditory canal? - The canal may be absent, stenotic,
oedematous, or filled with wax, debris, blood, or a foreign body. You may be able to remove
material to obtain a better view, but if there is a strong possibility of a perforation in the
tympanic membrane, the patient should be referred to an ear, nose, and throat surgeon as
syringing can damage the middle ear structures in such patients.
Can I see the tympanic membrane or the handle of the malleus, or both? - The deeper part of the
canal can again be obscured by wax or other material. Rarely the membrane and malleus may be
completely absent - for example, after certain ear operations. The handle may be visible even if
most of the pars tensa is absent; the handle gives you an indication of where the membrane
should have been.
Is the tympanic membrane intact? - Be careful to note the difference between a retracted drum
and a perforation. Usually the small blood vessels in the middle ear mucosa give you a clue. If
there is any debris or white keratin around the edge of the pars tensa or, more commonly, over
the pars flaccida the patient may have an occult cholesteatoma (skin debris within the middle ear
cavity) and should be referred for a specialist opinion.
Is the tympanic membrane the right colour and transparency? - Although the normal appearance
of the membrane varies greatly, a gold or blue colouration or a dull membrane usually indicates
fluid in the middle ear. White patches in the membrane are called tympanosclerosis. Small chalk
patches are extremely common. Thicker tympanosclerotic plaques are usually due to previous
surgery. Both types usually have no clinical importance unless the results of tuning fork tests are
abnormal.
Common problems
I can't see properly - It is important to check the light is adequate and the battery is fully
recharged. An undercharged unit will produce a poor light and subtle changes in the colour of the
tympanic membrane may not be accurately detected.
All I can see is a red drum - What you are most likely to be looking at is the posterior canal wall.
Try tilting the otoscope anteriorly and superiorly or pulling the pinna slightly further to
straighten out the canal and assist your view.
The anatomy is so abnormal I can't work out what is what - Try looking for the lateral process of
the malleus. Even if most other structures have been destroyed this is often visible. Once you can
identify the lateral process, orientation will be much easier.
I'm not sure if there is a perforation or not - In most cases a perforation is obvious, but the sharp
mouth of a deep retraction pocket can look remarkably similar. If you can see blood vessels in
the middle ear mucosa these confirm the presence of a perforation. If it is difficult to tell, an ear,
nose, and throat surgeon may use a pneumato-otoscope attachment, which fits into a socket in
the head of more expensive otoscopes. This attachment can produce negative or positive pressure
in the ear canal, producing visible movement in an intact drum.
Although this is not a comprehensive system, it should give you some idea of the likely
abnormality. If you are in any doubt refer the patient to an ear, nose, and throat specialist.
The following taken from the University of Bristol’s
wonderful web site:
http://www.bris.ac.uk/Depts/ENT/otoscopy_tutorial.htm
Otoscopes and otoscopy
Illumination is paramount. Run down batteries and dim lights will make
you job even more difficult and will sometimes alter your perception of
the image you see.
If you are handed an otoscope with worn out batteries, insist that they are
replaced. Most modern hand held otoscope have a very bright bulb that is
more than adequate for the job.
Use the biggest earpiece that you can fit in to the ear canal. Small
earpieces may be easy to use but the amount of visual information you
get is very limited.
Hold the otoscope at the end nearer the eyepiece, this way movement of
your hand and arm is not translated into as much movement of the tip of
the otoscope in the ear canal which may cause discomfort.
Holding the otoscope at the end like this can lead to increased
discomfort if you move your hand suddenly
The ear canal
The ear canal tends to have a slight anterior bulge and it is usually easier
to see the posterior part of the drum than the anterior part. The canal
may be partly straightened by pulling the pinna backwards and upwards
during examination. In infants pull the pinna more horizontally
backwards as the shape of the ear canal is different. In addition, the
angle of the drum may appear different in small children, with the top of
the drum appearing more lateral than the inferior part.
Note the appearance of the ear canal including it's diameter and the
presence of wax. It is usual to see some wax in almost every ear.
Larger deposits may obscure the view of the drum, but this does not
necessarily imply that the wax is causing deafness. The canal needs to
be almost completely obstructed to case hearing loss.
Wax is not normally present in the inner third of the ear canal. It's
presence there may indicate inappropriate use of cotton buds to clean
the ears of it may be a dried up crust, overlying more significant
pathology such as a perforation or cholesteatoma
In otitis externa, an infective / inflammatory condition, the canal may be
so swollen that a view into the ear is impossible
In swimmers, divers and surfers, chronic cold water exposure can lead
to the growth of bony swellings in the canal known as exostoses. These
are generally asymptomatic when small, but when larger can interfere
with the drainage of wax and predispose to infections such as otitis
externa
These black dots (spores) are the appearance of fungal infection
(aspergillus niger) with other fungi the spores may be white or yellow
This is chronic otitis externa. Although the canal wall is not swollen, the
skin is excoriated and red. The drum is essentially normal.
Foreign body in the canal of a child (wax crayon) note the drum visible
distal to the foreign body
The Normal Eardrum
Normal Eardrum
Normal
right
eardrum,
annotated
version
appears
below
see below
for
annotations
An annulus fibrosus
Lpi long process of incus - sometimes visible through a healthy translucent drum
Um umbo - the end of the malleus handle and the centre of the drum
Lr light reflex - antero-inferioirly
Lp Lateral process of the malleus
At Attic also known as pars flaccida
Hm handle of the malleus
There is no substitute for looking at as many drums as you can to give you an idea of what is
normal and what is abnormal. Look in your fellow students ears to start with.
Shape of the eardrum
The drum is slightly convex being most medial at the end of the malleus handle or umbo.
Abnormalities of shape are important, the drum may be bulging our, suggesting increased middle
ear pressure, such as in acute otitis media, or retracted inwards with negative middle ear
pressure, which is one of the otoscopic findings in glue ear.
Mild retraction may be difficult to identify. The
margin of the drum (annulus may become more
pronounced as in this image
As the drum retracts so does the handle of the
malleus and it may appear to be shortened on
otoscopy. The lateral process will also become
much more prominent than normal
As the drum becomes increasingly retracted, it
drapes over the ossicular chain, and the incus
and stapes head may be outlined
Eventually, nearly all the middle ear space may
be lost and the drum comes into contact with
the medial wall of the middle ear (this is known
as atelectasis)
Bulging ear drums are usually fairly obvious and a result of increased middle ear pressure. The
most likely cause of this is acute otitis media when the drum will not only bulge outwards, but is
usually very red because of hyperaemia and infection. Unfortunately I have found good images
of acute otitis media hard to come by because the patients are usually very young and not over
disposed to sit still to have pictures taken!
Color of the Drum
The normal drum is quite translucent and does not really appear to be any color except perhaps
grey. The color of the drum can be changed by thickening of the drum itself, injection of blood
vessels, or the presence of something behind it such as glue, pus or blood.
Compare this drum with the normal one. It is opaque and pale. There
is slight injection of blood vessels. This is one appearance of glue ear
Glue ear may make the drum yellow or even darker than normal. Note
also how retracted this drum is and how prominent the lateral process
of the malleus appears. Blood in the middle ear will give the ear a blue
or brown colour, this is called a haemotympanum.
Bubbles
You may see bubbles behind the drum. This represents a resolving
middle ear effusion, as air gradually re-enters the middle ear.
In this image, the bubbles appear much larger
White patches
white patches actually on the drum or within the drum itself are
usually tympanosclerosis, which is deposition of calcium into the
drum itself in response to trauma or infection. This is not normally of
any consequence unless it is severe, which can lead to a mild
conductive hearing loss.
If the white patch is behind the drum, this may represent
cholesteatoma (keratin in the middle ear). This normally needs to be
treated surgically.
Red / blue Lesions on the drum
A diffusely red drum usually represents otitis media. More localised
areas of discoloration can represent infection or vascular abnormalities
behind the drum.
This small red lesion at the tip of the malleus handle is a vascular
lesion called a glomus tumour. This might cause pulsatile tinnitus, but
is rare. This needs surgical treatment.
This red bulge in the canal is another glomus tumour (glomus
jugulare). this is the tip of a much larger lesion involving the temporal
bone.
This red raised lesion on the posterior aspect of the drum is likely to
be a granulation. Granulations are a localised infective process and
may be a sign of more serious underlying disease such as
cholesteatoma.
Perforations
You need to be able to distinguish between safe and unsafe
perorations. A safe perforation is exactly what it sounds like: a hole
in the tympanic membrane. The main risk of safe perforations are
that they may allow infection to enter the middle ear but there are
rarely more serious sequelae.
Safe perforation of the anterior part of the drum. A common cause of
perforations in this position is a persistent defect after the extrusion
of a grommet.
Inferior perforation. This is more likely to be as a result of chronic
middle ear infection.
Posterior perforation. Although posterior perforations may represent
more serious disease such as cholesteatoma, this is well described
and dry. It is possible to make out the posterior margin of this defect.
Traumatic perforations (e.g barotrauma) are often posterior and liner,
like a tear rather than a round hole.
Unsafe perforations are not in fact holes in the drum, they represent a
retraction of the tympanic membrane. Essentially a part of the drum
becomes sucked inwards and may gradually enlarge. When the
retraction becomes extensive, keratinous debris builds up in the
retraction and may become infected. This is essentially how acquired
cholesteatoma develops. Cholesteatoma is a dangerous lesion
because it is capable of eroding through bone and may cause serious
and even life threatening complications - hence the use of the term
unsafe.
Any defect or apparent perforation in the attic must be considered
unsafe and should be referred for ENT assessment. This crust in the
attic represents a large underlying cholesteatoma sac.
A posterior perforation where the posterior margin of the drum is
also potentially unsafe. In this image, not only is the posterior margin
of the drum not visible (you can imagine a retraction disappearing
behind the posterior margin to the right of the picture) but there are
granulations and crusting in the attic.
Granulations like this are often associated with underlying disease,
particularly if they arise in the attic.
Realistically speaking, in primary care consultation it may not be
possible to make out much of the anatomy of the drum in
cholesteatoma as the ear is filled with infected discharge. An ear
looking like this will need to be referred for ENT clinic and aural
toilet and microscopy.
If you are unable to see the drum, clinical features pointing towards
serious middle ear disease include:




persistent offensive discharge
long history of middle ear disease
significant hearing loss
previous mastoid or middle ear surgery
Grommets
This is a grommet (ventilating tube) in the correct position in the
drum. The hole in the middle should be clear of debris. Note a small
dried crust above the grommet which is unimportant and may be a
small clot remaining from surgery.
Just because you can see a grommet in the ear does not mean it is
working. This one is clearly extruding and on it's way out up the
canal. Note the drum visible in the distance.
This grommet is in the correct position but is covered in infective
granulation and blocked up. This will not be doing any good and
may be responsible for a chronic discharge. Note also the extensive
tympanosclerosis on the drum.
This is a T-tube which is a permanent sort of grommet designed not
to extrude on it's own. These are not commonly used as they lead to
a greater risk of perforation after removal, but in selected cases are
preferable to repeated insertions of standard pattern tubes.